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HENRY c. LEWIS, orV ESSEX, CONNECTICUT.

Letters Patent No. 60,207, dated December 4. 1866.

` SPEOIFICA'ION. To lAIJI. WHOM IT MAY coNcERN:

`Be it known that I, HENRY C. LEWIS, of Essex, in the county of Middlesex, and State of Connecticut, have invented a new Improvement in4 Countersinlr Bit; and I do hereby declare the following, when taken in connection with the accompanying drawings, and the letters of reference marked thereon, to be a full, clear, and exact I description of the same, and which said drawings constitute part of this specification, and represent, in- Figure 1, a front side view. Figure E?, a back side view. Figure 3, a section crossing :1: 11:; and `in Figure 4, a vertical central section. My invention consists in combining a eountersinkwith a bit so that when the hole of the screw to beinserged is bored to therequisite depth the same instrument will countersink` for the head, and positively'eentml with the hole itself. In boring for screws, the common practice. is to withdraw the boring instrument and employ a` separate and independent instrument to countersink for the head ofthe screw, and unless extraordinary care is used in thus `countersinking, the countersink is not central with the hole. This entraordinary care required, together with the inconvenience of changing the instrument, induces .the workman to drive the screw without countersinking, forcing the wood away as the head penetrates, generally tearing and disfiguring vthe wood.. i .By my invention these diiculties are entirely overcome; and that others may be enabled to construct and use my improvement, I will proceed to describe the same as illustrated in the accompanying drawings..`

l A is the bit; B the shank, terminating in any convenient form for insertion into the brace. 'At the proper distance from the point of the bit--that is to say, according to the size of the screw for which the hole is bored- I form an enlargement, C, its under surface being that of an inverted half cone'and corresponding to the under surface of the head of the screw; this enlarged portion is made concave upon one surface, as seen ings. `1,- 3, and 4, and so as to form a sharp cutting edge at 'a, (see iig. 3,) similar to theA cutting edge upon the bit,.thus using the proper-sized bit for the screwl to be driven. The hole and countersink aremade in` the mos-t perfect manner, and this construction is much cheaper than the ordinary countersink.`

Having thus fully described my invention, what I claim as new and useful, and desire to secure by Letters A eountersink bit constructed in the manner herein described', and so as to operate as and for the purpose specified. v

HENRY C. LEWIS.

Witnesses:

HENRY L. PRATT,

ALBERT PRATT. 

